This invention relates to apparatus for the wet crushing of material, particularly malt or barley, comprising a storage container for the material having a rotary feeder forming the lower closure thereof, a crushing mill and means for delivering and removing steeping water for the material to be crushed.
In so-called wet crushing (for preparing the mash in a beer-making process) the material (malt or barley) first has to be steeped in water. The entire quantity of material is supposed to be steeped as uniformly as possible without any inclusions of air so that particularly uniform size-reduction is obtained during the subsequent crushing operation. The glume of the material is supposed to be moistened in such a way that it remains largely intact during the crushing operation.
Hitherto, steeping of the material before wet crushing has generally been carried out in a storage container (malt barrel) arranged above the crushing mill, into which the steeping water is introduced from above or below or which is flooded for the duration of the steeping operation. In these known embodiments, therefore, steeping is carried out in batches. A certain quantity of material is exposed for a certain period to the action of the steeping water in the malt barrel and is subsequently crushed. Accordingly, those quantities of material which are only wet crushed at the end of a batch are exposed to the action of the steeping water (contact liquid) for a much longer period than the quantities crushed immediately after steeping. This gives rise to differences in the composition of the crushed material which adversely affect the subsequent brewing process in various respects.
In another known wet crushing apparatus (German Pat. No. 110,227), a steeping zone is present between the storage container and the crushing mill, the material being continuously passed through this steeping zone by means of mechanical feed systems (for example shafts provided with stirrer arms and blades). Although it is possible with an arrangement such as this to obtain a substantially uniform steeping time for all the particles of material, the feeding mechanism required necessitates a considerable outlay for equipment.